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Publication numberUS4142009 A
Publication typeGrant
Application numberUS 05/800,152
Publication dateFeb 27, 1979
Filing dateMay 24, 1977
Priority dateAug 13, 1974
Publication number05800152, 800152, US 4142009 A, US 4142009A, US-A-4142009, US4142009 A, US4142009A
InventorsColin T. Kyte, Geoffrey J. Lewis, Edgar Pearce, Keith Hume
Original AssigneeFosroc International Limited
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of treating timber with composition having a colloidal pigment
US 4142009 A
Abstract
An agent for stabilization of a decorative finish is incorporated in a timber preservative composition comprising a preservative e.g. fungicide, insecticide or fire retardant in an organic solvent e.g. white spirit, chlorinated hydrocarbon such as methylene chloride or a liquified butane or propane for use in a double vacuum treatment of the timber. The agent may be an alkyd resin or colloidal pigment of a defined mean particle size, or both.
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Claims(4)
What is claimed as the invention is:
1. A method of treating timber comprising subjecting the timber to a first vacuum, applying a liquid organic preservative composition to the timber, optionally applying a positive pressure to the liquid composition, said vacuum and said pressure being applied in a sufficient amount and for a sufficient time to permit the liquid composition ot penetrate the timber on all surfaces thereof, said liquid composition comprising a preservative composition in an organic solvent and a colloidal pigment being present in the preservative composition in an amount from about 3% to about 25% by weight, said colloidal pigment having a mean particle diameter size in the range of about 0.02 micron to about 1 micron, said colloidal pigment being present in an amount sufficient to enhance the grain pattern of the timber, removing the liquid composition, applying a second vacuum to the timber to remove excess liquid composition and releasing the second vacuum.
2. A method according to claim 1 in which the content of the colloidal pigment is about 10% to about 20% by weight.
3. A method according to claim 1 in which the preservative is selected from the group consisting of a fungicide, insecticide and fire retardant.
4. A method according to claim 1 in which the organic solvent is selected from the group consisting of a petroleum hydrocarbon, a chlorinated hydrocarbon and a liquified butane or propane.
Description

This application is a continuation of copending Application Ser. No. 497,161, filed Aug. 13, 1974, entitled Treatment of Wood, now U.S. Pat. No. 4,062,991, patented Dec. 13, 1977.

The invention relates to the preservation of timber (including timber composites) and in particular concerns methods of preserving and decorating timber preferably but not exclusively by means of a so-called double vacuum system of the type described and claimed in U.S. Pat. No. 3,859,046 in which an organic solvent preservative composition is used.

It is known to subject preserved timber to a further treatment in order to enhance its resistance to moisture and also its decorative appearance. One method of doing this is by applying a paint film and another is by applying a so-called stain to the timber which will enhance its natural grain effect. Whichever system is adopted there are difficulties in applying it on a commercial scale in relation to timber which has been treated by a double vacuum process using an organic solvent preservative composition. Thus, in the case of the subsequent painting there is a tendency for relatively poor adhesion between the paint and the treated wood and also a deterioration of the gloss of a finishing paint coat. Further it is necessary for a delay to occur before the subsequent painting may be done. In the case of the staining, this can be done to a stack of timber within the treatment vessel of a double vacuum process but there is a tendency for an uneven finish to be obtained as between timber making up one part of the stack and another. As a result, because of this colour difference, not all of the timber making up the stack is commercially acceptable which results in wastage.

It is an object of this invention to provide a method of treating timber by a double vacuum process in which the timber to be treated is prepared to receive without unacceptable delay, a firmly adherent high gloss paint finish or which has an even stain. In this way, a double vacuum process, it is possible to obtain a relatively high quality commercially attractive and preserved product.

According to the invention there is provided a method of treating timber comprising:

CONTACTING THE TIMBER WHILE UNDER AN INITIAL VACUUM WITH AN ORGANIC PRESERVATIVE COMPOSITION, WHICH COMPOSITION COMPRISES A PRESERVATIVE IN AN ORGANIC SOLVENT AND ALSO CONTAINS AN AGENT WHICH WILL PENETRATE INTO THE TIMBER TO FACILITATE THE STABILISATION OF A DECORATIVE FINISH,

OPTIONALLY APPLYING A POSITIVE PRESSURE,

REMOVING THE PRESERVATIVE COMPOSITION FROM THE TIMBER,

APPLYING A SECOND VACUUM TO REMOVE EXCESS PRESERVATIVE COMPOSITION, AND

RELEASING THE SECOND VACUUM.

In the case of a paint decorative finish to be applied subsequently, the agent in question preferably comprises an air oxidising resin or oil (which customarily will also be present in the paint). Because the same ingredient is present both in the preserved timber and in the subsequently applied paint there is a tendency for an improved bonding of the paint to the timber. Typically, the air oxidising agent will tend to be an alkyd resin which, in order that it will air oxidise will tend to be of the long oil type, i.e. it will have a relatively high content (say of the order of 50%) of oil in the solid resin. A alkyd resin may be prepared by modifying a polyhydric alcohol with an oil and reacting the modified alcohol with an agent such as phythalic anhydride or the like. An example of a polyhydric alcohol is glycerol or pentaerithyritol and suitable modifying oils include linseed, tung, fish, soya and dehydrated caster oils.

The content of the air oxidising resin or oil or other agent in the preservative composition is preferably in the range of from about 3% to about 25% by weight, conveniently 10% to about 20% by weight. If the concentration exceeds the upper limit there is a tendency for the viscosity of the preservative composition to become unacceptable.

In the case of a stain, the agent in question is preferably a colloidal pigment having a mean particle diameter size in the range of 0.02 micron to about 1 micron. By the use of this type of agent a grain staining decorative finish is stabilised. If the particle is below the defined limit not only does the pigment tend to penetrate the timber but when the excess solvent is extracted and evaporated off at the second vacuum stage the pigment is brought back to the timber surface; conversely if the pigment particle size is too coarse it will not permeate evenly between closely piled timber when stacked insidie the timber plant of the double vacuum process. Both agents may be present in the one preservative composition.

The preservative may be a fungicide and/or insecticide and/or fire retardant. The solvent may be an organic solvent of the type customarily used in timber preservation and is preferably a petroleum hydrocarbon of the white spirit type or a chlorinated hydrocarbon recoverable solvent such as methylene chloride or a liquified butane or propane.

The double vacuum presure impregnation may be carried out by the techniques described and claimed in our patent above mentioned.

The invention includes timber when preserved by the method and also, as new compositions of matter, the preservative compositions above defined.

In order that the invention may be well understood, Examples will now be given by way of illustration only.

EXAMPLE I

A preservative composition of the invention was formulated adding ingredients specified below the order inicated to the white spirit solvent.

______________________________________Ingredient           parts of weight______________________________________fungicide            1.5insecticide          0.5long oil alkyd resin 15.0methyl ethyl ketoxime                1.0water repellent      0.7white spirit         81.3                100.0______________________________________

A load of redwood timber (Pinus sylvestris) was treated with the preservative composition according to the technique of our U.S. Pat. No. 3,859,046 under the following conditions:

drawing of a initial vacuum of about -380 mm Hg for 3 minutes flooding with preservative composition

application of a positive pressure of about 760 mm

Hg for about 3 minutes

removal of the preservative composition

application of a final vacuum of about -630 mm Hg for at least 20 minutes.

The timber was removed from the treatment vessel and subjected to the evaluations below.

In a first comparative evaluation, different panels of Pinus sylvestris containing both heartwood and sapwood and each measuring 300 mm 100 mm 15 mm were treated as described above, with a preservative composition which was free of the long oil alkyd resin, and left untreated (control). Each panel was dipped in an alkyd-based primer paint, the treated panels being dipped 60 minutes after treatment with the respective preservative composition. All three sets of specimens were exposed to the weather in a horizontal position for nine weeks. The strength of the adhesion between the primer paint film and the timber was then measured using a hand tensiometer. The results obtained expressed as percentage difference relative to the control panels were as follows:

______________________________________controls (untreated)      100panels treated with preservativecomposition having no alkyd resin                      54panels treated with preservativecomposition of the invention                     104______________________________________

These results show that the inclusion of the alkyd resin in the preservative compostion improves the adhesion of the primer paint film to the preserved wood.

In a second comparative evaluation three sets of panels as in the first evaluation were primed with a fast drying alkyd primer of the type used in the timber industry within 30 minutes following treatment with the preservative composition (except for the control). Undercoat and gloss paint coatings were then applied to the panels at 24 hour intervals. After drying it was observed that the gloss finish of the panels treated with the preservative composition of the invention was similar to that of the control panels, whereas that using the alkyd resin-free preservative composition was inferior. The following gloss reflectance meter readings were noted:

______________________________________ untreated control panels                        71% panels treated with preservative Composition having no alkyd resin                        59% panels treated with the preservative composition of the invention                        83%______________________________________

The results show that it is possible to apply a primer and paint coating to wood treated with preservative composition according to the invention within a relatively short period following treatment with the preservative composition without deteriorating the gloss of the finish paint coating. This is not the case where the wood has been treated by means of a preservative composition which lacks the alkyd resin ingredient.

EXAMPLE II

A preservative composition was made by adding the ingredients specified below in the order indicated to the white spirit solvent.

______________________________________                 partsIngredient            by weight______________________________________  fungicide          1.5  insecticide        0.5  long iol alkyd resin                     15.0  methyl ethyl ketoxime                     1.0  water repellent    0.7  transparent colloidal ferric  hydroxide pigment                     10.0  disperesed in toluene 40%,  solvent            71.3                     100.0______________________________________

Teh preservative composition was used to treat spruce (Picea abies) and (Picea sitchensis) by a double vacuum impregnation technique according to U.S. Pat. No. 3,859,046 and under the following conditions:

drawing of a initial vacuum of about -630 mm Hg for 1 hour flooding with preservative composition

application of a positive pressure of about 380 mm Hg for about 1 hour

removal of the preservative composition

application of a final vacuum of about -600 mm Hg for at least 20 minutes.

In this case, the load of timber treated comprises boards which were stacked one on top of another within the treatment vessel. Despite this, on examination of the load following treatment the pieces of timber were found to have an enhanced grain pattern which was uniform irrespective of whether the piece was at the top, bottom or at the side of the stack.

In the Examples reference has been made to a fungicide and insecticide and examples of such agents include tributyl tin oxide, gamma benzene hexachloride and penta chloro phenol.

EXAMPLE III

A preservative composition was made up by adding the following ingredients to white spirit.

______________________________________                     partsIngredient                by weight______________________________________    fungicide                 1.5    insecticide               0.5    hydrocarbon co-solvent for fungicide                         10    water repellent           0.7    transparent colloidal ferric    hydroxide, 40%    dispersed in toluene      10    white spirit              77.3                         100.0______________________________________

The composition prepared in this way used to treat timber by a double vacuum process according to the techniques above described. The timber was stacked in a close density and following treatment was inspected when it was observed that the individual pieces of timber were stained to a uniform density irrespective of their position within the stack contained in the treatment vessel and to a depth of about 3 mm from any lateral surface, both in heartwood and sapwood.

These Examples illustrate the value of adding to an organic preservative composition in a double vacuum process an agent which will stabilize a decorative finish, which agent can be an alkyd resin or a colloid pigment of defined mean particle size or both of these agents together.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3547849 *Apr 13, 1967Dec 15, 1970Du PontAlkyd modified vinyl acetate-ethylene copolymer emulsion paint
US3859046 *Aug 21, 1972Jan 7, 1975Fosroc AgApparatus and process for the treatment of timber
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4233929 *Jan 8, 1979Nov 18, 1980Protim International LimitedApparatus for the treatment of timber
US4305976 *May 12, 1980Dec 15, 1981Zubiate Robert GDiammonium phosphate for wood
US7632567Aug 31, 2007Dec 15, 2009Osmose, Inc.Micronized wood preservative formulations comprising copper and zinc
US7674481Apr 9, 2004Mar 9, 2010Osmose, Inc.Micronized wood preservative formulations
US8158208Sep 12, 2008Apr 17, 2012Osmose, Inc.Method of preserving wood by injecting particulate wood preservative slurry
US8168304 *Jan 21, 2010May 1, 2012Osmose, Inc.Micronized wood preservative formulations comprising boron compounds
US8409627Jul 15, 2009Apr 2, 2013Osmose, Inc.Particulate wood preservative and method for producing the same
US8460759 *Sep 29, 2008Jun 11, 2013Osmose, Inc.Micronized wood preservative formulations
US8603576Mar 29, 2011Dec 10, 2013Osmose, Inc.Compositions and methods for treating cellulose based materials with micronized additives
US8637089Sep 26, 2006Jan 28, 2014Osmose, Inc.Micronized wood preservative formulations
US8722198Apr 13, 2012May 13, 2014Osmose, Inc.Method of preserving wood by injecting particulate wood preservative slurry
US8747908Oct 21, 2004Jun 10, 2014Osmose, Inc.Micronized wood preservative formulations
US8747909Jun 20, 2008Jun 10, 2014Osmose, Inc.Micronized wood preservative formulations
US8778407May 14, 2008Jul 15, 2014Osmose, Inc.Micronized wood preservative formulations
US20090293761 *May 17, 2005Dec 3, 2009Richardson H WayneComposition for wood treatment comprising an injectable aqueous wood preservative slurry having sparingly-soluble biocidal particles and pigments
EP1802458A2 *Oct 18, 2005Jul 4, 2007Osmose, Inc.Micronized wood preservative formulations
Classifications
U.S. Classification427/297, 427/298, 118/50, 427/441, 422/33, 427/393, 427/440
International ClassificationB27K5/02, B27K3/50, B27K3/52
Cooperative ClassificationB27K3/007, B27K5/02, B27K3/0278, B27K3/50, B27K3/08, B27K2240/30
European ClassificationB27K3/00N, B27K3/02Z, B27K3/08, B27K3/50, B27K5/02